The debate over tablets continues. Apple seems to be having trouble making iPads fast enough. But competing tablets such as the Motorola Xoom reportedly haven't sold well, and RIM's BlackBerry PlayBook is off to a rocky start. The question is whether people really want tablets--in addition to a smartphone and PC--or just want an iPad.

One problem is that so far the challengers have been charging roughly the same prices for their tablets as Apple does for the iPad. The Xoom starts at $599 with 32GB of storage and Wi-Fi. The PlayBook , which has a smaller display, is $499 with 16GB and $599 with 32GB. The Wi-Fi version of the iPad 2 is the same price: $499 with 16GB and $599 with 32GB.

The average price of a Windows PC is much less than a Mac. And most smartphones sell for less than the iPhone 4. Similarly companies can't expect to sell Android, QNX, webOS or Windows tablets for the same price as an iPad. The simple fact is the iPad 2 has better hardware, better software and the best app store.

Over the next week or so, several companies will begin selling less expensive tablets. The Acer Iconia A500 Tablet is now available for pre-order at Best Buy for $449.99. The Iconia A500 has a 10-inch display, Nvidia Tegra 2 processor, 16GB of storage and Android 3.0 (Honeycomb). The Asus Eee Pad Transformer goes on sale in the U.S. tomorrow starting at $399.99 with 16GB and $499.99 with 32GB. It has a 10-inch IPS display, Tegra 2 processor and Android 3.0. The Eee Pad Transformer also has an optional docking station with a keyboard for an additional $150.

These less expensive models should provide us with a better idea of whether tablets are just a fab, as Microsoft CTO Craig Mundie recently suggested, or as Goldman Sachs wrote in a report last week, "one of the most disruptive forces in computing in nearly three decades."